This invention relates generally to fiber optic connectors and, more particularly, to a method of terminating the inner fiber core of a fiber optic cable relative to the mating end of a fiber optic connector.
It is generally known in the industry that an optical "fiber" conventionally includes a core surrounded by a cladding, both of which normally are of glass but with different indexes of refraction. However, in the specification and claims herein the terms "core" or "fiber core" will be used to denote this composite element of the fiber optic cable.
The terminal end surface of an inner fiber core for use in lightwave transmission must be flat and, normally, polished to minimize insertion losses. The inner fiber core typically must also be axially, laterally, and angularly aligned within certain parameters to establish an excellent optical coupling between two fiber optic cables. The success achieved in the development and production of fiber optic cables therefore has focused strongly upon low loss connectors and couplers for such cables, including in-line connectors. The ability to design, manufacture, deploy and service a data transmission line, for instance, requires suitable connectors in order to assure the continued progress of the fiber optics field. Accordingly, connectors for this and other applications are being developed which can be used without any significant increase in insertion losses.
Many fiber optic connectors presently available are precision, expensive instruments providing very low insertion losses, but they are designed for certain applications such as long distance applications in telephonic systems and in other applications requiring extremely low insertion losses where expensive low loss connectors may be employed. It has been found, however, that expensive low loss connectors are not always well suited for applications requiring a large number of connectors where very expensive connectors are not economically feasible. For instance, in such applications as computers and other data transmission applications, a large number of fiber optic cables are employed and there is a continuing need for low cost, low loss fiber optic connectors which minimize insertion losses due to fiber end surface preparation.
Heretofore, low cost, low loss fiber optic connectors have been manufactured by providing a connector portion for receiving the fiber optic cable with a length of the inner fiber core, stripped of its outer coating, protruding from a mating end of the connector. The stripped core then is cleaved or cut off outside the connector and subsequently polished flush with the mating end of the connector. Alternatively, the stripped fiber core has been cleaved to a predetermined length and then placed in the connector with the core end protruding slightly beyond the mating end of the connector. The slight protrusion then is polished flush with the mating end of the connector. All of these prior methods of terminating the inner fiber core relative to the mating end of the connector require a separate polishing step to provide a flat, smooth end surface of the core to minimize insertion losses.
The present invention is directed to a new method of terminating the inner fiber core relative to the mating end of the connector, in which subsequent polishing or other preparation of the core end is completely eliminated.